A work machine (such as a hydraulic excavator and a bulldozer) includes a vehicle body provided with a traveling device, an work implement provided on the vehicle body, and a cab for work machine provided on the vehicle body and serving as a driving room, on which an operator operates the work implement and the traveling device.
The cab for work machine includes a frame body formed by welding ends of a plurality of steel pipe members to each other, sheet metal members to cover the side surfaces of the frame body. Rigidity of the cab is ensured by the frame body formed by welding the steel pipe members to each other. On the other hand, the cab for work machine is provided with a window frame and the like to which a windowpane and the like is mounted.
An opening/closing mechanism for an opening member such as a window frame and a door includes a hinge mechanism, which is provided on one end of the side edge of the opening member, and a slide mechanism for sliding the window frame and the door along the side surface of the cab for work machine.
Conventionally, there has been known a slide type opening/closing mechanism in which a rail is attached along a pipe member that forms a frame body, so that a window frame, a door or the like is slidably supported by the rail. As such a slide type opening/closing mechanism, there has been known an arrangement in which a pair of pipe members, which form the frame body and have deformed cross section, opposing each other are employed, and each of the pipe members has a rail incorporated thereinto (refer to, for example, Patent Document 1).
Further, as such a slide type opening/closing mechanism, there has been known another arrangement in which a pair of rails are directly fixed along, by means of welding or the like, a pair of pipe members, which form a frame body, opposing each other (refer to, for example, Patent Document 2).
[Patent Document 1] Japanese Patent Laid-Open Publication No. 2001-207479 (Paragraph Number [0027], Paragraph Number [0028], FIG. 1, FIG. 2 and others)
[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-106824 (Paragraph Number [0027], FIG. 2 and others)